1. Field
Embodiments relate to an apparatus and method for recognizing the position of a mobile robot, and more particularly, to an apparatus and method for recognizing the position of a mobile robot, in which the lighting of a light-emitting source and the speed of a mobile robot are controlled according to illuminance in order to recognize the position of the mobile robot even at night with lights turned off and in which a captured image determined to have lights turned on is processed so that features of the captured image, which can be changed according to whether lights are turned on or off, remain unchanged regardless of whether the lights are turned on or off in order to enhance the efficiency of recognizing the position of the mobile robot.
2. Description of the Related Art
Mobile robots are used to move or assemble products at industrial sites and to clean the house and move objects at home. In order for mobile robots to be used at industrial sites and at home, it is very important for the mobile robots to be able to accurately recognize their positions and directions.
Self-position recognition technology is divided into relative self-position recognition technology and absolute self-position recognition technology. According to the relative self-position recognition technology, a mobile robot recognizes its relative position using an odometer such as an encoder, and a distance measurer that uses an ultrasonic sensor or a laser. According to the absolute self-position recognition technology, a mobile robot recognizes its absolute position by detecting the position of an artificial mark, which is attached to a predetermined place in a room, or the position of a natural object.
Specifically, when using the relative self-position recognition technology, a mobile robot can build an environmental map on its own and autonomously travel based on the environmental map even if no information about an environment in which the mobile robot is to travel is given in advance. However, as the traveling time of the mobile robot increases, errors of position recognition by an encoder, i.e., an odometer, may accumulate due to a slip phenomenon. In particular, these position recognition errors are increased by collisions or avoiding motions. In addition, when a user artificially changes the position of the mobile robot, the mobile robot may not be able to recognize its position.
In this regard, research is being conducted on the absolute self-position recognition technology which enables a mobile robot to estimate its position using given information about an environmental map and feature information of its surroundings even when the mobile robot cannot recognize its position.
The absolute self-position recognition technology compares features of an image of a mark on a ceiling, which was captured by an imaging device, to those of a pre-stored image of the mark in order to recognize the position of a mobile robot. However, when illuminance of a room is low, it is difficult to capture images of the mark. In addition, if a captured image of the ceiling includes lights, pixel values and sizes of the lights are recognized significantly different when the lights are on and off, thereby causing errors in recognizing the position of the mobile robot.